NL2029550B1 - Method and device for determining evaluation index of effective reinforcement range - Google Patents

Method and device for determining evaluation index of effective reinforcement range Download PDF

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Publication number
NL2029550B1
NL2029550B1 NL2029550A NL2029550A NL2029550B1 NL 2029550 B1 NL2029550 B1 NL 2029550B1 NL 2029550 A NL2029550 A NL 2029550A NL 2029550 A NL2029550 A NL 2029550A NL 2029550 B1 NL2029550 B1 NL 2029550B1
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tamping
ram
evaluation index
test
effective
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NL2029550A
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Dutch (nl)
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Ou Yangjian
Qian Guoping
Lu Yunbin
Yang Ziling
Liu Yayan
Gong Xiangbing
Yu Huanan
Huang Peng
Li Xi
Li Ping
He Zhongming
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Univ Changsha Science & Tech
Guangzhou Congpu Expressway Co Ltd
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Priority to NL2029550A priority Critical patent/NL2029550B1/en
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    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D3/00—Improving or preserving soil or rock, e.g. preserving permafrost soil
    • E02D3/02—Improving by compacting
    • E02D3/046—Improving by compacting by tamping or vibrating, e.g. with auxiliary watering of the soil
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D13/00—Accessories for placing or removing piles or bulkheads, e.g. noise attenuating chambers
    • E02D13/06—Accessories for placing or removing piles or bulkheads, e.g. noise attenuating chambers for observation while placing

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  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Structural Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Paleontology (AREA)
  • Civil Engineering (AREA)
  • Mining & Mineral Resources (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Agronomy & Crop Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Soil Sciences (AREA)
  • Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
  • Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)

Abstract

The present invention discloses a method and a device for determining an evaluation index of an effective reinforcement range, wherein the method comprises the steps of constructing a dynamic compaction reinforcement foundation mechanism test model, and performing multiple groups of dynamic compaction tests on the dynamic compaction reinforcement foundation mechanism test model; in each group of tests, selecting both a and MH“ as fixed values, changing ram weights M and drop distances H, and enabling each ram weight M and the corresponding drop distance H to form a tamping mode, acquiring an effective reinforcement depth corresponding to each tamping mode, taking different values of d and MH“ corresponding to different groups of tests, and looking up to determine whether the effective reinforcement depths corresponding to multiple tamping modes in each group of tests are the same, and if the effective reinforcement depths are the same, then MH“ corresponding to the group of tests is the evaluation index of the effective reinforcement range. The application provides a novel evaluation index of an effective reinforcement range. When the evaluation index is unique, the corresponding effective reinforcement depth is unique. Therefore, the evaluation index can reveal the reinforcement mechanism of the ram weight M and the drop distance H on the soil body and provide substantial improvement

Description

METHOD AND DEVICE FOR DETERMINING EVALUATION INDEX OF
EFFECTIVE REINFORCEMENT RANGE
TECHNICAL FIELD
[01] The present invention relates to the related technical field of civil engineering, in particular to a method and a device for determining an evaluation index of an effective reinforcement range.
BACKGROUND ART
[02] Inthe dynamic compaction method, fillers are layered and paved, and a ram is used for dropping from a preset height to perform layered compaction on the soil body, so that the soil 1s impacted to form dense areas of varying degrees centered on the tamping point. The effective reinforcement range is the core parameter to determine the thickness of uncompacted layer and the distance between tamping points, and is also an important theoretical index to control the quality of dynamic consolidation and to characterize the dynamic response of soil.
[03] At present, the research on the effective reinforcement range mainly focuses on the reinforcement depth. Referring to formula (1), the tamping energy MH is converted by the correction coefficient c to finally obtain the effective reinforcement depth d.
[04] d= MH Formula (1)
[05] In formula (1), the tamping energy MH is an independent variable, and the effective reinforcement depth d is a dependent variable. According to the uniqueness principle, under the condition that the independent variable MH is the same, the unique dependent variable d should be obtained. However, a large number of tests show that, when the tamping energy MH is the same, the effective reinforcement depths d obtained by the two tamping modes of “heavy ram low drop (M is large, and H is small)” and “light ram high drop (M is small, and H is large)” are not the same.
Therefore, the evaluation index using the tamping energy MH as the effective reinforcement range is not accurate, and the reinforcement mechanism of the soil body by the weight M and the drop distance H of the ram is not revealed.
[06] Therefore, how to provide an evaluation index of an effective reinforcement range and an acquisition method thereof so as to reveal the reinforcement mechanism of the ram weight M and the drop distance H on the soil body in the dynamic compaction process becomes an urgent problem to be solved in the art.
SUMMARY
[07] The present invention aims to provide a method for determining an evaluation index of an effective reinforcement range, which can solve the problem that an existing evaluation index using tamping energy MH as the effective reinforcement range cannot accurately reveal the reinforcement mechanism of ram weight M and drop distance H on the soil body.
[08] Itis also an object to provide a device for determining an evaluation index of an effective reinforcement range.
[09] In a first aspect, an embodiment of the present application provides a method for determining an evaluation index of an effective reinforcement range, comprising:
[10] constructing a dynamic compaction reinforcement foundation mechanism test model, and performing multiple groups of dynamic compaction tests on the dynamic compaction reinforcement foundation mechanism test model,
[11] in each group of tests, selecting both a and MH as fixed values, changing ram weights M and drop distances H, and enabling each ram weight M and the corresponding drop distance H to form a tamping mode; acquiring an effective reinforcement depth corresponding to each tamping mode;
[2] taking different values of a and MH” corresponding to different groups of tests; and
[13] looking up to determine whether the effective reinforcement depths corresponding to multiple tamping modes in each group of tests are the same, and if the effective reinforcement depths are the same, then MH* corresponding to the group of tests is the evaluation index of the effective reinforcement range.
[14] In one possible embodiment, constructing a dynamic compaction reinforcement foundation mechanism test model comprises:
[15] paving test soil samples in layers, and arranging a dyed soil sample between two adjacent layers of the test soil samples as a marking layer;
[16] setting a collection point for collecting dynamic stress parameters in the test soil sample; and
[17] introducing a digital imaging unit, and adjusting an imaging range of the digital imaging unit, wherein the imaging range needs to meet the requirement of the digital imaging unit to record the position change of the marking layer.
[18] In one possible embodiment, paving test soil samples in layers is performed before setting the collection point for collecting dynamic stress parameters in the test soil sample; and after arranging a dyed soil sample between two adjacent layers of the test soil samples as a marking layer, the method further comprises:
[19] introducing a Mariotte bottle, wherein the Mariotte bottle and the test soil sample form a U-shaped water passage; and adjusting a water level in the Mariotte bottle so that the water level in the Mariotte bottle is consistent with the water level in the test soil sample.
[20] In one possible embodiment, the test process for each tamping mode comprises:
[21] arranging an acceleration sensor on a ram, the acceleration sensor being used for acquiring an acceleration time history of the ram;
[22] freely falling the ram from a corresponding drop distance, and performing multiple tamping processes on the same tamping point;
[23] during two adjacent tamping processes of the same tamping point, if a tamping amount of the tamping point is smaller than a preset value, the test of the tamping mode 1s finished.
[24] In one possible embodiment, acquiring an effective reinforcement depth for each tamping mode comprises:
[25] collecting soil body dynamic response information in each tamping mode; the soil body dynamic response information comprises dynamic stress parameters of the test soil sample, position change of the marking layer and acceleration time history of the ram; and
[26] acquiring, according to the soil body dynamic response information, the effective reinforcement depth corresponding to each tamping mode.
[27] In one possible embodiment, in the step of acquiring, according to the soil body dynamic response information, the effective reinforcement depth corresponding to each tamping mode, a displacement field of the test soil sample after multiple tamping in each tamping mode is acquired according to the position change of the marking layer; and the effective reinforcement depth corresponding to each tamping mode is determined according to the displacement field of the test soil sample.
[28] In a possible embodiment, in the step of taking different values of a and MH* corresponding to different groups of tests, the value of a is between 0 and 1.
[29] In the second aspect, the embodiment of the application provides a device for determining an evaluation index of an effective reinforcement range, the device determines the evaluation index of the effective reinforcement range according to the aforesaid method for determining the evaluation index of the effective reinforcement range; the device comprises:
[30] a test box provided with a plurality of layers of test soil samples, with a marking layer being arranged between every two adjacent layers of test soil samples; wherein one side surface of the test box is a transparent side surface;
[31] multiple rams of different masses provided with through holes on both sides of the center of mass;
[32] a guide mechanism comprising two guide sliding rods used for guiding a falling path of the ram when the ram penetrates through the guide sliding rods and falls freely from a preset height, and a hoisting mechanism used for moving the ram to the preset height;
[33] a data collection mechanism comprising a dynamic stress sensor used for collecting dynamic stress parameters in the test soil sample in each tamping mode, digital imaging unit used for recording position changes of the marking layer in each tamping mode and an acceleration sensor used for acquiring an acceleration time history of the ram. 5 [34] In a possible embodiment, the device further comprises a Mariotte bottle which is communicated with one of the sides of the test box and forms a U-shaped water passage.
[35] Compared with the prior art, the present application has the beneficial effects that:
[36] The application provides a method for determining an evaluation index of an effective reinforcement range, by which, a new evaluation index for the effective reinforcement range can be determined. When the evaluation index is unique, the corresponding effective reinforcement depth is unique, so that the evaluation index can reveal the reinforcement mechanism of the ram weight M and the drop distance H on the soil body and provide substantial improvement suggestions for the current specification.
BRIEFT DESCRIPTION OF THE DRAWINGS
[37] In order to more clearly describe the technical solutions in the embodiments of the present application, the drawings used in the description of the embodiments are briefly described below. It should be understood that the following drawings only show certain embodiments of the application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained from these drawings without involving any inventive effort. |38] FIG. 11s a schematic diagram of a method for determining an evaluation index of an effective reinforcement range according to an embodiment of the present application;
[39] FIG. 2 is a front view of a device for determining an evaluation index of an effective reinforcement range according to an embodiment of the present application;
[40] FIG. 3 is a right view of a device for determining an evaluation index of an effective reinforcement range according to an embodiment of the present application,
[41] FIG. 4 is a graphical representation of ram weights M, drop distances H, and
MH? values for a different tamping mode according to an embodiment of the present application; and
[42] FIG. 5 is a bottom view of a ram according to an embodiment of the present application.
[43] wherein:
[44] 10 test box; 11 water outlet hole; 12 monitoring hole; 20 ram; 21 through hole; 22 screw; 30 guide mechanism; 31 guide sliding rod; 32 lifting bracket; 40 hoisting mechanism; 41 magnet; 42 wire rope; 43 motor; 44 pulley; 45 steel wire rope drum rack; 50 data collection mechanism; 51 dynamic stress sensor; 52 digital imaging unit; 53 pore water pressure sensor; 54 humidity sensor; 60 Mariotte bottle; and 70 server.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[45] The embodiments of the present application are described in further detail below with reference to the accompanying drawings, which are intended to be illustrative only and not limiting of the present application.
[46] In the description of the present application, it is to be understood that the terms “top”, “bottom”, “upper”, and “lower”, and the like, refer to orientations or positional relationships based on the orientations or positional relationships shown in the drawings, or the orientations or positional relationships in which the products of the present application are conventionally placed in use, merely for convenience in describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present application.
[47] In the description of the present application, it is to be noted that, unless explicitly stated and defined otherwise, the term “connection” is to be interpreted broadly. For example, the connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above-mentioned terms in this application can be understood according to specific circumstances.
[48] According to one aspect of the present application, a method for determining an evaluation index of an effective reinforcement range is provided. Referring to FIG.1, the method comprises the following steps:
[49] SI, constructing a dynamic compaction reinforcement foundation mechanism test model, and performing multiple groups of dynamic compaction tests on the dynamic compaction reinforcement foundation mechanism test model.
[50] In one embodiment, constructing a dynamic compaction reinforcement foundation mechanism test model comprises the following steps:
[51] Step 1), paving test soil samples in layers, and arranging a dyed soil sample between two adjacent layers of the test soil samples as a marking layer. Wherein, the thickness of each test soil sample is preferably 10 cm.
[52] Step 2), setting a collection point for collecting dynamic stress parameters in the test soil sample.
[83] Wherein, a tamping point is preset on a test soil sample, and a plurality of dynamic stress sensors is embedded in the horizontal direction and the height direction of the test soil sample below the tamping point, with the arrangement density of the dynamic stress sensors near the tamping point being larger than that of the dynamic stress sensors far away from the tamping point. The dynamic stress sensor is used for collecting dynamic stress parameters of different positions of the test soil sample, and acquiring, according to the dynamic stress parameters, dynamic stress propagation and dissipation information of the test soil sample in a subsequent tamping process and after tamping.
[54] Step 3), introducing a digital imaging unit, and adjusting an imaging range of the digital imaging unit, wherein the imaging range needs to meet the requirement of the digital imaging unit to record the position change of the marking layer.
[55] Wherein, the basic principle of the digital imaging unit is as follows: firstly, the position distribution of each marking layer is recorded by using the digital imaging unit to form a particle initial position image. Then, after each subsequent tamping is completed, the position change of each marking layer is recorded by using the digital imaging unit to form a position image after deformation. The deformed position image is compared with the particle initial position image, and the position change of the marking layer before and after tamping is analyzed to acquire the displacement change of each layer of test soil sample and the displacement field information of the test soil sample. The displacement field information of the soil sample subjected to each tamping test is summarized to obtain the displacement field of the test soil sample subjected to multiple tamping tests. [S6] The imaging range of the digital imaging unit is adjusted to align the imaging range of the digital imaging unit with the test soil sample position corresponding to the tamping point, so that the digital imaging unit records the position change of the marking layer.
[57] Preferably, the step 1) of paving test soil samples in layers is performed before the step 2) of setting the collection point for collecting dynamic stress parameters in the test soil sample; and after paving test soil samples in layers, and arranging a dyed soil sample between two adjacent layers of the test soil samples as a marking layer, it further comprises:
[58] introducing a Mariotte bottle, wherein the Mariotte bottle and the test soil sample form a U-shaped water passage; and adjusting a water level in the Mariotte bottle so that the water level in the Mariotte bottle is consistent with the water level in the test soil sample. The U-shaped water passage is used for simulating the underground water level, water in the test soil sample is discharged from the test soil sample in the subsequent tamping process, and the plastic deformation amount of the whole test soil sample is determined according to the water discharge amount of the test soil sample and the effective stress principle.
[59] S2. In each group of tests, selecting both a and MH" as fixed values, changing ram weights M and drop distances H, and enabling each ram weight M and the corresponding drop distance H to form a tamping mode; and acquiring an effective reinforcement depth corresponding to each tamping mode.
[60] In one embodiment, in each group of tests, based on the same principle as “MH®*" when the value of o is taken as a fixed value, rams of different masses are selected and the corresponding drop distances H are selected according to the weight
M of the ram. Each ram weights M and the corresponding drop distance H form a tamping mode. When the weight M of the ram and the corresponding drop distance H need to meet the requirements of tamping the test soil sample, the test soil sample could generate obvious changes without reflection wave in the test boundary.
[61] Preferably, the ram is formed by stacking a plurality of semi-circular steel discs with the same diameter, and the mass of the ram can be adjusted by adjusting the number of the semi-circular steel discs so as to adjust the weights of the ram. The radius of the semicircular steel disc may be selected to be 100 mm, and the thickness may be selected to be 10 mm.
[62] The test process of each tamping mode comprises the following steps:
[63] arranging an acceleration sensor on a ram, the acceleration sensor being used for acquiring an acceleration time history of the ram; wherein, according to the ram acceleration time history, ram displacement and ram dynamic stress time history characteristics can be further clarified;
[64] freely falling the ram from a corresponding drop distance, and performing multiple tamping processes on the same tamping point;
[65] during two adjacent tamping processes of the same tamping point, if a tamping amount of the tamping point is smaller than a preset value, the test of the tamping mode is finished. The preset value in the step of tamping amount of the tamping point is smaller than a preset value can be selected to be 20 mm.
[66] In one embodiment, acquiring an effective reinforcement depth for each tamping mode comprises the following steps:
[67] collecting soil body dynamic response information in each tamping mode; the soil body dynamic response information comprises dynamic stress parameters of the test soil sample, position change of the marking layer and acceleration time history of the ram; and
[68] acquiring, according to the soil body dynamic response information, the effective reinforcement depth corresponding to each tamping mode. Specifically, a displacement field of the test soil sample after multiple tamping in each tamping mode is acquired according to the position change of the marking layer; and the effective reinforcement depth corresponding to each tamping mode is determined according to the displacement field of the test soil sample.
[69] S3, taking different values of o and MH? corresponding to different groups of tests. The value of a is between 0 and 1. For example, FIG. 4 lists the ram weights M, drop distances H, and MH* values for different tamping modes in each of the test groups, with a values being 0.25, 0.3, 0.5, and 1, respectively. According to the test requirements, the values of a can be adjusted adaptively, which is not limited to the values listed in FIG. 4.
[70] S4, looking up to determine whether the effective reinforcement depths corresponding to multiple tamping modes in each group of tests are the same, and if the effective reinforcement depths are the same, then MH" corresponding to the group of tests is the evaluation index of the effective reinforcement range.
[71] For example, taking each test group of FIG. 4 as an example, when the value of a 15 0.25, the effective reinforcement depths of the multiple tamping modes of this group are different; when the value of a is 0.3, the effective reinforcement depths of multiple tamping modes of this group are different; when the value of a is 0.5, the effective reinforcement depths of multiple tamping modes of this group are the same; and when the value of a is 1, the effective reinforcement depths of this group are different.
[72] When the value of a is 0.5, the effective reinforcement depth of multiple tamping modes of this group is the same, that is, the tamping effect of the multiple tamping modes is the same, then MH’? corresponding to tests of this group is the evaluation index of the effective reinforcement range. That is, the unique evaluation index corresponds to the unique effective reinforcement depth. The evaluation index
MH"? can reveal the compaction mechanism of ram weight M and drop distance H to the soil, and provide useful reference for scientific research of soil dynamic characteristics and dynamic compaction engineering practice.
[73] According to one aspect of the present application, a device for determining an evaluation index of an effective reinforcement range is provided. The device determines the evaluation index of the effective reinforcement range according to the method for determining the evaluation index of the effective reinforcement range of the aforesaid examples.
[74] Referring to Figs. 2 and 3, the device comprises a test box 10, a plurality of rams 20 of different masses, a guide mechanism 30 and a hoisting mechanism 40, and a data collection mechanism 50.
[75] the test box 10 is provided with a plurality of layers of test soil samples 10 with a marking layer being arranged between every two adjacent layers of test soil samples. The test box 10 is a cubic structure with an open top, and one of the sides is a transparent side for observing the deformation of the test soil sample. The dimensions of the test box 10 are 1.0 m x 0.5 m x 1.0 m. For example, the transparent side surface may be made of transparent tempered glass, and other non-transparent side surfaces and bottom surfaces may be made of aluminum alloy sheets. A damping rubber layer is arranged on the non-transparent side surface used for avoiding interference of shock wave reflection when the test soil sample is tamped.
[76] A Mariotte bottle 60 is connected to one of the side surfaces of the test box 10 and forms a U-shaped water passage with the test box 10. The water level in the
Mariotte bottle 60 is adjusted to adjust the water level in the test soil sample. The
U-shaped water passage is used for simulating the underground water level, water in the test soil sample is discharged from the test soil sample in the subsequent tamping process, and the plastic deformation amount of the whole test soil sample is determined according to the water discharge amount of the test soil sample and the effective stress principle. Specifically, the lower side of the left side of the test box 10 1s provided with a water outlet hole 11, which is connected to the Mariotte bottle 60.
[77] Referring to FIG. 5, the ram 20 is formed by stacking a plurality of semi-circular steel discs with the same diameter, and the mass of the ram 20 can be adjusted by adjusting the number of the semicircular steel discs, thereby adjusting the weight of the ram 20. The radius of the semicircular steel disc may be selected to be 100 mm, and the thickness may be selected to be 10 mm. Based on Pappus's theorem, the distance between the center of mass and the center of the circle is 4R/37. When the radius of the ram 20 is 100 mm, the distance between the center of the ram and the center of the ram is 42.5 mm. The two sides of the center of mass of the ram are provided with through holes 21, and the distance between the centers of the two through holes 21 is 115 mm. The semicircular steel disc located at the lowermost part of the ram 20 is welded with two screw rods 22 which are respectively arranged at two sides of the center of mass of the ram used for preventing deflection caused by eccentricity when the ram 20 falls freely. The distance between the centers of the two screws 22 is 155 mm.
[78] The guide mechanism 30 comprises two guide sliding rods 31 and a lifting bracket 32. The lifting bracket 32 is connected to the top of the test box 10, and the height of the lifting bracket 32 is adjustable. For example, the lifting bracket 32 comprises a transverse plate and four longitudinal plates. One end of the four longitudinal plates is fixed to the test box 10, the other end of the four longitudinal plates is connected to each corner of the transverse plate by bolts, and the height of the lifting bracket 32 can be adjusted by adjusting bolts. The ram 20 is arranged on two guide sliding rods 31 penetrating through the through holes on two sides of the center of mass of the ram 20, and the guide sliding rods 31 are used for guiding a falling path of the ram 20 when the ram 20 falls freely from a preset height.
[79] Each guide sliding rod 31 is connected with the transverse plate, a guide ring is arranged at the connection position of the guide sliding rod 31 and the transverse plate.
The center line of the guide ring coincides with the center line of the corresponding through hole in the ram 20 to ensure that the guide sliding rod 31 is in a vertical state in the freely falling process of the ram 20 and that the ram 20 cannot be twisted freely in the free falling process. The position of the bottommost part of the guide sliding rod 31 can be adjusted by adjusting the guide ring to ensure that the height between the position of the bottommost part of the guide sliding rod 31 and the test soil sample in the test box 10 is just the thickness of the ram 20.
[80] The hoisting mechanism 40 comprises a magnet 41, a motor 43, a pulley 44 and a steel wire rope 42 connected to the magnet 41. The motor 43 and the pulley 44 are fixed on the transverse plate, and the steel wire rope 42 is wound on the pulley 44.
One end of the steel wire rope 42 is fixed on a steel wire rope drum rack 45, and the other end of the steel wire rope 42 is connected with the magnet 41. When the motor 43 supplies power to the magnet 41, the magnet 41 attracts the ram 20, and the steel wire rope 42 moves the magnet 41 and the ram 20 to the preset height. When the motor 43 does not supply power to the magnet 41, the magnet 41 releases the ram 20 from the preset height, so that the ram 20 freely falls under the guiding action of the guide sliding rod 31. The magnet 41 is chosen to be electromagnet ZYE-P80/38.
[81] The data collection mechanism 50 comprises a plurality of dynamic stress sensors Sl, a digital imaging unit 52, an acceleration sensor, a pore water pressure sensor 53, and a humidity sensor 54. The plurality of dynamic stress sensors 51, the digital imaging unit 52, the acceleration sensor, the pore water pressure sensor 53, and the humidity sensor 54 are all connected to a server 70 for analyzing the collected data and transmitting the collected data to the server 70.
[82] The plurality of dynamic stress sensors 51 are embedded in the horizontal direction and the height direction of the test soil sample below the tamping point, with the arrangement density of the dynamic stress sensors 51 located near the tamping point being larger than that of the dynamic stress sensors 51 far away from the tamping point. The dynamic stress sensor 51 is used for collecting dynamic stress parameters of different positions of the test soil sample in each tamping mode, determining, according to the dynamic stress parameters, a stress wave propagation rule, and in turn acquiring dynamic stress propagation and dissipation information in the test soil sample in the subsequent tamping process and after the tamping.
[83] The digital imaging unit 52 is located a preset distance from the test box 10, and the imaging range of the digital imaging unit 52 is aligned with the test soil sample position corresponding to the tamping point, so that the digital imaging unit 52 records the position change of the marking layer in each tamping mode. For each tamping mode, the position change of the marking layer before and after tamping is analyzed, and the position change of the marking layer before and after tamping is analyzed to acquire the displacement change of each layer of test soil sample and the displacement field information of the test soil sample. The displacement field information of the soil sample subjected to each tamping test is summarized to obtain the displacement field of the test soil sample subjected to multiple tamping tests. According to the displacement field of the test soil sample, the effective reinforcement depth corresponding to each tamping mode can be determined.
[84] An acceleration sensor is provided on the ram 20 for acquiring a ram acceleration time history when the ram 20 falls freely. Wherein, according to the ram acceleration time history, ram displacement and ram dynamic stress time history characteristics can be further clarified;
[85] A plurality of monitoring holes 12 are respectively provided on the left and right sides of the test box 10, with the monitoring holes 12 being used to pass through wires for connecting the pore water pressure sensor 53 and the server 70. The pore water pressure sensor 53 is used to monitor the distribution of pore water pressure of the soil sample when tamping the test soil.
[86] A humidity sensor 54 is used to acquire the moisture content and saturation of the test soil sample.
[87] The dynamic stress sensor 51, the digital imaging unit 52, the acceleration sensor, the pore water pressure sensor 53 and the humidity sensor 54 can acquire changes and distribution rules of parameters such as the dynamic stress, stress wave, test soil sample displacement field, ram acceleration, pore distribution, pore water pressure, water content and saturation in the test soil sample during and after the tamping of the ram 20. The parameter data are used for analyzing the change rules of particle rearrangement, inter-particle pore reduction, pore water discharge, compaction of the test soil sample and the like in the test soil sample, revealing the impact action rule of the weight of the ram and the drop distance on the test soil sample, and further fully revealing the dynamic compaction reinforcing mechanism.
[88] It can be seen from the above technical solutions that, by the method for determining an evaluation index of an effective reinforcement range provided by application, a new evaluation index for the effective reinforcement range can be determined. When the evaluation index is unique, the corresponding effective reinforcement depth is unique, so that the evaluation index can reveal the reinforcement mechanism of the ram weight M and the drop distance H on the soil body and provide substantial improvement suggestions for the current specification.
[89] The above are only the preferred embodiments of this application. It should be pointed out that for those of ordinary skill in the art, without departing from the technical principles of this application, several improvements and substitutions can be made, and these improvements and substitutions should also be regarded as the scope of this application.

Claims (9)

Conclusies l. Werkwijze voor het bepalen van een evaluatie-index van een effectief verstevigingsbereik, gekenmerkt door deze het volgende omvat: het construeren van een dynamischecompacteringsfunderingsverstevigingsmechanisme-testmodel, en het uitvoeren van meerdere groepen van dynamischecompacteringstests op het dynamischecompacteringsfunderingsverstevigingsmechanisme-testmodel ; het in elke groep van tests als vaste waarden selecteren van zowel a- als MH®, het wijzigen van ramgewichten M en valafstanden H, en het in staat stellen van elk ramgewicht M en de overeenkomstige valafstand H om een aandrukmodus te vormen; het verkrijgen van een effectieve verstevigingsdiepte die overeenkomt met elke aandrukmodus; het nemen van verschillende waarden voor a en MH" die overeenkomen met verschillende groepen van tests; en het opzoeken om te bepalen of de effectieve verstevigingsdieptes die overeenkomen met meerdere aandrukmodi in elke groep van tests hetzelfde zijn, en indien de effectieve verstevigingsdieptes hetzelfde zijn, dan 1s MH° die overeenkomt met de groep van tests de evaluatie-index van het effectieve verstevigingsbereik.Conclusions l. A method for determining an evaluation index of an effective reinforcement range, characterized by comprising: constructing a dynamic compaction foundation reinforcement mechanism test model, and performing multiple groups of dynamic compaction tests on the dynamic compaction foundation reinforcement mechanism test model; selecting both α- and MH® as fixed values in each group of tests, changing ram weights M and drop distances H, and enabling each ram weight M and the corresponding drop distance H to form a tamping mode; obtaining an effective reinforcement depth corresponding to each pressing mode; taking different values for a and MH" corresponding to different groups of tests; and looking up to determine whether the effective reinforcement depths corresponding to multiple compaction modes are the same in each group of tests, and if the effective reinforcement depths are the same, then 1s MH° corresponding to the group of tests the evaluation index of the effective gain range. 2. Werkwijze voor het bepalen van de evaluatie-index van het effectieve verstevigingsbereik volgens conclusie 1, met het kenmerk dat het construeren van een dynamischecompacteringsfunderingsverstevigingsmechanisme-testmodel het volgende omvat: het in lagen van bedekking voorzien van testgrondmonsters, en het als een als een markeringslaag tussen twee aangrenzende lagen van de testgrondmonsters rangschikken van een geverfd grondmonster; het instellen van een verzamelpunt voor het verzamelen van dynamischespanningsparameters in het testgrondmonster; en het introduceren van een digitale beeldvormingseenheid, en het aanpassen van een beeldvormingsbereik van de digitale beeldvormingseenheid, waarbij het beeldvormingsbereik dient te voldoen aan de vereiste dat voor de digitale beeldvormingseenheid om de positieverandering van de markeringslaag op te nemen.A method for determining the evaluation index of the effective reinforcement area according to claim 1, characterized in that constructing a dynamic compaction foundation reinforcement mechanism test model comprises: layering test soil samples, and using it as a marker layer arranging a painted soil sample between two adjacent layers of the test soil samples; setting a collection point for collecting dynamic stress parameters in the test soil sample; and introducing a digital imaging unit, and adjusting an imaging range of the digital imaging unit, the imaging range meeting the requirement for the digital imaging unit to accommodate the position change of the marker layer. 3. Werkwijze voor het bepalen van de evaluatie-index van het effectieve verstevigingsbereik volgens conclusie 2, met het kenmerk dat het in lagen van bedekking voorzien van de testgrondmonsters uitgevoerd wordt voorafgaand aan het instellen van een verzamelpunt voor het verzamelen van dynamischespanningsparameters in het testgrondmonster; en na het tussen twee aangrenzende lagen rangschikken van een geverfd grondmonster als een markeringslaag, waarbij de werkwijze verder het volgende omvat: het introduceren van een Mariottefles, waarbij de Mariottefles en het testgrondmonster een U-vormige waterdoorgang vormen; en het aanpassen van een waterniveau in de Mariottefles zodat het waterniveau in de Mariottefles consistent is met het waterniveau in het testgrondmonster.A method for determining the evaluation index of the effective reinforcement range according to claim 2, characterized in that layering of the test soil samples is performed before setting a collection point for collecting dynamic stress parameters in the test soil sample; and after arranging a painted soil sample as a marker layer between two adjacent layers, the method further comprising: introducing a Mariotte bottle, the Mariotte bottle and the test soil sample forming a U-shaped water passageway; and adjusting a water level in the Mariotte bottle so that the water level in the Mariotte bottle is consistent with the water level in the test soil sample. 4. Werkwijze voor het bepalen van de evaluatie-index van het effectieve verstevigingsbereik volgens een van conclusies 1 —3, met het kenmerk dat het testproces van elk van de aandrukmodi het volgende omvat: het op een ram rangschikken van een versnellingssensor, waarbij de versnellingssensor gebruikt wordt voor het verkrijgen van een versnellingstijdgeschiedenis van de ram; het vanaf een overeenkomstige valafstand vrij vallen van de ram, en het uitvoeren van meerdere aandrukprocessen op hetzelfde aandrukpunt ; indien, tijdens twee aangrenzende aandrukprocessen van het zelfde aandrukpunt, een aandrukmodus van het aandrukpunt kleiner is dan een vooraf ingestelde waarde, dan wordt de test van de aandrukmodus beëindigd.A method for determining the evaluation index of the effective gain range according to any one of claims 1-3, characterized in that the testing process of each of the pressing modes comprises: arranging an acceleration sensor on a ram, wherein the acceleration sensor used for obtaining a ram acceleration time history; free-falling the ram from a corresponding falling distance, and performing multiple pressing processes at the same pressing point; if, during two adjacent tamping processes of the same tamping point, a tamping mode of the tamping point is less than a preset value, then the tamping mode test is terminated. 5. Werkwijze voor het bepalen van de evaluatie-index van het effectieve verstevigingsbereik volgens conclusie 4, met het kenmerk dat het verkrijgen van een effectieve verstevigingsdiepte die overeenkomt met elke aandrukmodus het volgende omvat: het in elke aandrukmodus verzamelen van grondlichaamdynamischeresponsinformatie; waarbij de grondlichaamdynamischeresponsinformatie dynamischespanningsparameters van het testgrondmonster, positieverandering van de markeringslaag en versnellingstijdgeschiedenis van de ram omvat; en het volgens de grondlichaamdynamischeresponsinformatie verkrijgen van de effectieve verstevigingsdiepte die overeenkomt met elke aandrukmodus.A method for determining the evaluation index of the effective attenuation range according to claim 4, characterized in that obtaining an effective attenuation depth corresponding to each tamping mode comprises: collecting ground body dynamic response information in each tamping mode; wherein the soil body dynamic response information includes dynamic voltage parameters of the test soil sample, position change of the marker layer, and acceleration time history of the ram; and obtaining the effective reinforcement depth corresponding to each pressing mode according to the soil body dynamic response information. 6. Werkwijze voor het bepalen van de evaluatie-index van het effectieve verstevigingsbereik volgens conclusie 5, met het kenmerk dat in de stap van het volgens de grondlichaamdynamischeresponsinformatie verkrijgen van de effectieve verstevigingsdiepte die overeenkomt met elke aandrukmodus, een verplaatsingsveld van het testgrondmonster na meerdere aandrukkingen in elke aandrukmodus wordt verkregen volgens de positieverandering van de markeringslaag;, en de effectieve verstevigingsdiepte die overeenkomt met elke aandrukmodus bepaald wordt volgens het verplaatsingsveld van het testgrondmonster.The method for determining the evaluation index of the effective firming range according to claim 5, characterized in that in the step of obtaining the effective firming depth corresponding to each compaction mode according to the soil body dynamic response information, a displacement field of the test soil sample after multiple compactions in each tamping mode is obtained according to the position change of the marking layer; and the effective reinforcement depth corresponding to each tamping mode is determined according to the displacement field of the test soil sample. 7. Werkwijze voor het bepalen van de evaluatie-index van het effectieve verstevigingsbereik volgens conclusie 4, met het kenmerk dat in de stap van het nemen van verschillende waarden voor a en MH” die overeenkomen met verschillende groepen van tests, de waarde van ¢ zich tussen O en 1 bevindt.The method for determining the evaluation index of the effective gain range according to claim 4, characterized in that in the step of taking different values of α and MH" corresponding to different groups of tests, the value of ¢ is between 0 and 1. 8. Inrichting voor het bepalen van een evaluatie-index voor een effectief verstevigingsbereik, met het kenmerk dat: de inrichting de evaluatie-index van de effectieve verstevigingsdiepte bepaalt volgens een van de conclusies 1 — 7; waarbij de inrichting het volgende omvat: een testbak die voorzien is van een veelheid van lagen van testgrondmonsters, waarbij een markeringslaag is gerangschikt tussen elke twee aangrenzende lagen van het testgrondmonster, waarbij één zijde van de testbak een transparant zijoppervlak is; meerdere rammen met verschillende massa’s die aan beide kanten van het zwaartepunt voorzien zijn van doorgaande gaten; een geleidingsmechanisme dat twee glijdende geleidestaven omvat die gebruikt worden voor het geleiden van een valpad van de ram wanneer de ram door de glijdende geleidestaven heen steekt en vanaf een vooraf ingestelde hoogte vrij naar beneden valt, en een hijsmechanisme dat wordt gebruikt voor het naar de vooraf ingestelde hoogte verplaatsen van de ram; een dataverzamelmechanisme dat is voorzien van een dynamischespanningssensor die gebruikt wordt voor het in elke aandrukmodus verzamelen van dynamischespanningsparameters in het testgrondmonster, een digitale beeldvormingseenheid die gebruikt wordt voor het in elke aandrukmodus opnemen van positieveranderingen van de markeringslaag, en een versnellingssensor die gebruikt wordt voor het verkrijgen van een versnellingstijdgeschiedenis van de ram.An apparatus for determining an evaluation index for an effective reinforcement range, characterized in that : the apparatus determines the evaluation index of the effective reinforcement depth according to any one of claims 1 to 7; the apparatus comprising: a test tray having a plurality of layers of test soil samples, a marker layer being arranged between any two adjacent layers of the test soil sample, one side of the test tray being a transparent side surface; multiple rams of different masses with through holes on both sides of the center of gravity; a guide mechanism comprising two sliding guide bars used to guide a fall path of the ram as the ram passes through the sliding guide bars and falls freely down from a pre-set height, and a hoisting mechanism used for moving to the pre-set set height moving the ram; a data collection mechanism comprising a dynamic strain sensor used to collect dynamic strain parameters in the test soil sample in each tamping mode, a digital imaging unit used to record position changes of the marker layer in each tamping mode, and an acceleration sensor used to obtain of a ram acceleration time history. 9. Inrichting voor het bepalen van de evaluatie-index van het effectieve verstevigingsbereik volgens conclusie 8, gekenmerkt door het verder omvatten van: een Mariottefles die in verbinding gesteld is met één van de zijden van de testbak en een U- vormige waterdoorgang vormt.Apparatus for determining the evaluation index of the effective attenuation range according to claim 8, characterized by further comprising: a Mariotte bottle connected to one of the sides of the test tank and forming a U-shaped water passage.
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